Looper mechanism for sewing machines



- 1,681,901 J. R. MOFFATT LOOPER MECHANISM FOR SEWING MACHINES Flled Oct 20 1921 3 Sheets-Sheet l A E] A Aug. 21, 1928.

1,681,901 J. R. MOFFATT LOOPER MECHANISM FOR SEWING MACHINES Filed Oct. $0. 1921 3 Sheets-Sheet 2 QL'HIIIIIN" Aug. 21, 1928.

J. R. MOFFATT LOOPER MECHANISM FOR SEWING MACHINES a Sheets Shet 3 Filed (m 20, 1921 Patented Aug. 21, 1928.

U N! T ED A .P Item OFFICE.

JAMES R. MOFFATT,-,OF.GHIGAGO, ILLINOIS, ASSIGNOR flTO UNION SPECIAL MACHINE COMP-ANY, OF CHICAGO,;ILLINOIS, -A CORPORATION OFJLLINOIS.

LQOPER MECHANISM FOR SEWING MACHINES.

Application filed October 20, 1921.

' The invention relates to new and useful improven'ients in looper mechanism for sewing machines, and more particularly'to a looper mechanism which'is adapted to be used in a ,5 work supporting arm.

An object of the invention is to provide a jlooper operating mechanismforzawork supporting arm which is so constrnctedthat the looper shaft which extends longitudinally of ,M) the work supporting arm is given a dwell in its oscillations when the looper'is at thefforward end of its. stroke and substantially :while saidL looper is bei:ng;moved laterally to avoid the needle.

A further object of the invention is to provvi'de a looper operating'inechanism of the above type wherein the means for moving the jlooper shaft longitudinally for giving to the looper its needle avoiding movement is-capa- ,H l)l6 of adjustment so that the lateral stroke imparted to the looper maybe varied.

A still further object of the invention is to provide a machine of the above type, wherein thework supportingarm is carried by and projectslaterally from a vertically riding ranie. member into which the opering shart extends.

'hcse and other objects will inpart be obvious and will in part be hereinafter more is fu! v disclosed.

in the drawings which show by way-o'f-il lustration one embodimentzof the invention- Figure 1.is a view pa'rtlyi'n vertical sect on and partly in side elevationof a portion of a sewing machine embodying my improve- ,Jnents;

Figure 2 is a sectional view on the line2f2 of Fig. 1;

Figure 3 is a sectional view on the line 3-3 of Fig. 1; I

Figure 4C is .a sectional view on the-line 4-. of Fig. 1; v p Figure an enlargedlongitudinal sec- .ionzil view through the vertically extending .(l and the rear portion of the work suparm and showingthelooper shaft .ng mechanism in side elevation;

.6 is.a perspective view of the rocker no the looper shaft endwise andthe l vThrive saown the-invention as appliedto H nachine of the type disclosed in the te b grantedtoLansing Onderdonk De tannins. 1906. No. 839,077. Said machine has ,a framemember extending horizontally Serial No. 508;!)30.

extending'mcmber andreceive their 'moveme-nts from th-e operating shaft which projects into this vertically extending member. On the shaft is, a rotating eccentric and'bctween this rotating eccentric and a radially projecting arm carried bythe looper shaft "isa train 0 f mechanism including toggle links which are so timed and disposed as to appreach and pass slightly the dead center when the looper is at the forward end of its stroke, and thus it is that a dwell is given to the looper in its oscillations while the'looper is in the needle thread loop. The looper shaft is moved endwise by a rock lever which is turn --is oscillated by aneccentric strapco-operating withan eccentric on the operating shaft. The eccentric strap has anadjustable connection with the rock llever so that the extent of oscillations impartedto the rock lever may be varied and thus'the amount of lateral movementgiven to the looper may be varied.

Referring more in detail to the drawings, I 3 have shown the invention as embodiedin a machine vwhich includes, a horizontally extending frame member 1, and this horizontally extending member as more clearly shown "in the Onderdonk patent above referred to, is parallelwith the overhanging-arm. Projecting vertically "from this horizontallyex- .tendingframe member l is a vertical frame member 2. Located inthe'hor-izontally extending framewmembcr -1 is an operating shaft 3. This operating shaft, as clearly shown in the Ondcrdonkpatent, is rotated from the main driving shaft. Said operating shaft 3 projects into the vertically extending frame member 2 and projecting latorally from the upper end of the vertically extending frame member 2 is a work supporting arm 4. This work supporting arm 4; is comparatively small 111 cross section and is especially adapted for stitching garments having tubular parts.

The material being stitched is fed off from the end of the arm as the tube is formed. This is accomplished by a main feed dog 5 and an auxiliary feed dog 6. The material is held on the work support by a presser foot 7 indicated diagran'm'iatically in dotted lines A The machine may be provided vith a plurality of needles and these needles are set abreast and positioned as indicated in dotted lines at 8. .Co-operating with the needles beneath the work support is a single thread carrying looper 9. This thread carrying looper 9 is carried bya looper supporting shaft 10 which extends longitudinally of the work supporting arm 4. and is mounted for oscillation and endwise movement in bearings 11, 12 and 13.

The main feed dog 5 is carried by a feed bar 14. This feed bar 1a is mounted on links 15 which are pivotally attached to a lever 16, fulcrumed at 17 and connected to an eccentric strap 18 which co-operates with an eccentrio on the operating shaft 3. As this operating shaft rotates the lever 16 is oscillated and this gives the up and down movements to the feed bar 14:. The feed bar 14-, at the right-hand end thereof, as viewed in Figure l, is mounted so as to rock on a pin 19 and this pin 19 is capable of sliding in slots in the upper portion of the bearing 12. The feed bar is moved endwise on this hearing 12 by means of a link 20, which is pivoted at 21 to the feed. bar and at 22 to a slotted end of a lever 28. This lever 23 at its inner end is connected to an eccentric strap 24 wh1ch cooperates .with an eccentric on the main shaft. Through this lever the feed bar is given its endwis'e movement. i

The auxiliary feed dog 6 is carried by an auxiliary feed bar 25 which is mounted to slide on the main feed bar 14. so that the auxiliary feed bar is raised and lowered with the main feed bar. This auxiliary feed bar is moved back and forth by means of a lever 26 which is connected to the auxiliary feed dog at 27. This lever 26 has a fork at its lower end straddling a pin 28 which serves as a fulcrum pin for the lever. The lever is connected by a link 29 to the main feed bar 14, so

that as the main feed bar moves back and forth it will oscillate this lever 26 and this imparts a movement to the auxiliary feed bar'which may be different in extent from the movement imparted to the main feed bar.

This differential feeding mechanism which has been referred to briefly above forms no part of the present invention but is shown,-

described and claimed in my co-pending application Serial No. 508,931,1iled of even date herewith and patented April 21, 1925, No. 1,534,132.

The looper supporting shaft 10 is oscillated for moving the looper into and out of the needle thread loops. This is brought about by a link 30 which is connected to a ball 31 carried at the outer end of a radially extend ing arm clamped to the looper supporting shaft 10. This radially extending arm 32 is formed integral with a slit sleeve which is clamped to the looper shaft by means of a bolt The link 30 is connected at its lower end to a ball stud 34 carried by the arm 35 of a rock lever which is pivoted at 36 to the frame of the machine. This rock lever has a downwardly extending arm 37 which is pivoted at 38 to a link 89. The link 39 is pivoted at i0 to an arm or link 41 which is fixed to a short stub shaft a2 mounted in suitable hearings in the vertically projecting frame member 2. This link or arm d1 carries a ball-stud 43 to which an eccentric strap 4% is pivoted. This eccentric strap 4% co-operates with an eccentric 45 on the operating shaft 3.

. When the radially extending arm 32 is moved downwardly the looper is moved forward into the needleloop and when it is lifted or raised upwardly then the looper is retracted from the needle thread loop. It will be readily seen that the links 39 and ll constitute toggle links and they move from a point at one side of a line passing through the pivotal connection 38 and the center of the shaft 42 to a position substantially in said line or slightly to the other side thereof. lVhen these links are in the position shown in Fig. 5, that is, with the toggle links buckled, the radial arm 32 is raised and the looper is at the rear end of its stroke. When these toggle links are in alinement, as shown in F 1, then the looper is at the forward end of its stroke. It will be readily seen that the links approach a dead center and they pass said dead center line slightly and this occurs while the looper is at the forward end of its stroke, which gives to the looper a dwell at this time so that the looper moves forward into the needle thread loop and then comes substantially to a stop or dwell for a period of time and during this dwell it is moved laterally for its needle avoiding movement.

The needle avoiding movement is given to thelooper by means of a rock lever it. This rock lever 4:6 is shown in perspective in Fig. 6 of the drawings. It consists of a projecting arm d7 having a slot 48 therein and yoke arms 4t94t9. On the looper shaft 10 is a collar 50 which is loose on the shaft. This collar 50 carries projecting pins 5151 which extend through the ends of the yoke arms 49a9 and on the ends of the pins are nuts 5252. This rock lever 16 is mounted to oscillate freely on a short shaft 53 carried by the vertically projecting frame member 2.

(lo-operating with the eccentric on the mainshaft is an eccentric strap 54 and this eccentric strap 54. is connected to. a ball 55 Jun llf:

carried by the outer end of a short stud arm 56. This stud arm 56 is adjustably mounted in the slot 48 of the rock lever 46. Said stud is heldin adjusted positions by'means of a nut 57. By adjusting this stud 56 the amount of movement imparted to the rock lever 46 may be varied. The collar 50 which freely engages the looper supporting shaft is mounted on said shaft between two spaced collars 58 and 59. These spaced collars are fixed to the shaft and this permits the shaft to oscillate freely in the collar 50, but any endwise movement of the collar 50 will cause an end wise movement to the looper shaft. The shaft 53 which carries the rock lever 46 is held from endwise movement in the vertically projecting frame memberQ by collars 60 and 61.

The upper portion of the vertically projecting frame member 2 and the work supporting arm 4 is closed by a removable cover plate 62 which may be held in place in any suitable way. The side of the vertically projecting frame member 2 is cut to expose the parts of the looper operating mechanism and this is closed by a. cover plate 63. This gives ready access to the mechanism operated by the shaft 31 which imparts movements to the looper and also imparts movements to the feed dogs.

The operation of my device will be obvious from the description which has been given above. As the operating shaft 3 extending into the vertically projecting frame member 2 rotates it will oscillate the toggle links which in turn will give to the looper supporting shaft an oscillation. These toggle links approach or cross a dead center as the looper reaches the forward end of its stroke and as a result the looper dwells when it gets into the needle thread loop and remains. in the dwell substantially while the lateral movements are imparted thereto. The first part of the backward movement of the looper is comparatively slow, and this gives ample time for the needle to get down into the thread triangle. The backward movement of the looper increases in speed and the rear end of the looper movement is very rapid, said looper instantly starting forward to enter the needle thread loop and this movement of the looper is very quick until the point of the looper is passed well into the looper thread loop, after which the movement of the looper slows down until it comes to a dwell. These movements insure the perfect entrance of the looper into the needle thread loop and the needle inturn into the thread triangle which causes the looper thread loop to be left on the needle. The lateral movements imparted to the looper are derived from an eccentric on the shaft 3 and this is brought about through the rock lever having a slotted arm connection with the eccentric, so that the throw of the rock lever may be readily varied and thus the extent of lateral movement imparted to the looper may be changed. The slot 48 in the rock lever is preferably cut so as to be concentric with the center of the operating eccentric therefor when the looper is on the side of the needle passed by the looper as it enters the needle thread loop. Thus the looper may be set to pass very close to the needle and variaions in the lateral throw of the looper will not change the position at which the looper passes the needle.

It is obvious that minor changes in the details of construction and arrangement of parts may be made without departing from the spirit of the invention as set forth in the appended claims. I

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. The combination of a vertically extending frame member, a work supporting arm projecting laterally therefrom, an operating shaft extending into said frame member, 5. looper supporting shaft extending longitudinally of said work supporting arm, a threaded looper carried thereby, means actuated by said operating shaft for giving the looper supporting shaft anendwise movement, and independent means actuated by said operating shaft for oscillating said looper supporting shaft, said means including toggle links movable toward and from a dead center, said toggle links being in substantial alinement when the looper is at the forward end of its stroke and during the endwise movement of the looper shaft. 2. The combination of a vertically extendmg frame member, a work supporting arn projecting laterally therefrom, an operating shaft extending into said frame member, a looper supporting shaft extending longitudinally of said work supporting arm. a threaded looper carried thereby, means actuated by said operating shaft for giving the looper supporting shaft an endwise movement, and independent means actuated by said operating shaft for oscillating the looper shaft, said means including an eccentric, an eccentric strap, toggle links operated by said eccentric strap, a rock lever oscillated by the toggle links, and a link connecting the rock levef to the looper supporting shaft, said toggle links being in substantial alinement when the looper is at the forward end of its stroke and during the endwise movement of the looper shaft.

3. The combination of a vertically extending frame member, a work supporting arm projecting laterally therefrom, an operating shaft extending into said frame member. a looper supporting shaft extending longitudinally of said work supporting arm. a threaded looper carried thereby, means actuated by said operating shaft for giving the looper supporting shaft an endwise .movement, and independent means actuated by the operating shaft for oscillating the looper supporting shaft, said means including-an eccentric on the operating shaft, an eccentric strap, an oscillating arm to which said eccentric strap is connected, a rock lever, a link connecting said rock lever with said oscillatlever.

4. A sewing machine including in combination, a main frame structure, arotatable shaft mounted therein, a vertical member attached at one end to said frame, a laterally projecting work arm mounted at the. other end of said vertical member, a feeding mechanism including a four motion-feed dog mounted in said work supporting arm, a looper supporting shaft extending longitudinally of saidwork supporting arm, a threaded looper carried thereby, means actuated by said operating shaft for giving the looper supporting shaft an endwise movement, independent means actuated by said operating shaft for oscillating the looper shaft, and means independent of said oscillating means for the looper shaft and actuated by said operating shaft for giving said feed dog its movements.

5. A sewing machine including in combination, a main frame structure, a rotatable shaft mounted therein, a vertical member attached at one end to said frame, a laterally projecting work arm mounted at the other end of said vertical member, a feeding mechanism including a four motion feed dog mounted in said work supporting arm, a looper supporting shaft extending longitudinally of said work supporting arm, a threaded looper carried thereby, means actuated by said operating shaft for giving the looper supporting shaft an endwise movement, an eccentric on said operating shaft, means operated thereby for oscillating the looper shaft, an independent eccentric on said operating shaft, means operated thereby for raising and lowering the feed dog. and means actuated from said operating shaft for moving the feed dog back and forth.

6. A sewing machine including in combination, a main frame structure. a rotatable shaft mounted therein. a vertical member attached at one end to said frame, a laterally projecting work arm mounted atthe other end of said "ertical member, a feeding mechanism including a four. motion feed dog mounted in said work supporting arm, a

looper supporting shaft extending longitudinally of said work supportinguarm, a threaded loopercarriedthereby, means actuated by said operating shaft for, giving. the looper supporting shaft an endwise move :ment, an eccentric on said operating shaft,

means operated therebyfor. moving said looper supporting shaft endwise,,an independent eccentric on said operating shaft, means operated thereby for oscillating said looper shaft, a third independent eccentric on said operating shaft, means operated thereby for raising and lowering said feed dog, and means actuated fromsaid operating shaft for movingsaid feed dog/back and forth.

7. A sewing machine including in combination, a main frame structure, a rotatable shaft mounted therein, a vertical member attached atone end'of said frame, a laterally projecting work arm mounted at the other end of said vertical member, a feedingimechanism including a four motionfeed dog, a looperinechanism including a four'motion looper, four independent eccentrically set members carried by said mainshaft, devices actuated by one of said members for'moving the feed dog'back and forth, devices actuated from another of said members for raising and lowering said feed dog,-and devices actuated from anothermemberfor moving the looper into and out of the needle thread loop, and devices actuated from stillanother eccentric member for giving a lateral or needle avoiding movement to the looper.

8. The combination of a vertically extending frame member, a work supporting arm PI'OJQCiJlIlg laterally therefrom, an operating shaft. extending into "SEUCl'fIZLmB member, a

looper .supportingshaft extending longitudinally of said work supporting armand transversely across the said vertically extending frame member, said frame member having a bearing for the outer end of-said looper shaft, a threaded loopercarried by'said shaft, means for oscillatingsaid looper shaft from said operating shaft including an arm attached to said looper shaft. back from the end thereof, and independent means for moving said loopersupporting shaft endwise including an eccentric on the operating shaft, a sleeve on saidlooper shaft between said arm and the end bearing, spaced collars on the looper shaft for restraining the .endwise movement of the sleeve on said looper shaft a rock lever having anarm extending transversely ofthe frame member and connected to saideccentric, and-a yoke extending length wise of-said frame member and pivotally con nected to said sleeve. I

Intestimony whereof, Iafiix my signature.

JAMES R; MorrA'rr 

